The situation is heating up between Apple and retailers who are part of the Merchant Customer Exchange,a group that is developing its own mobile payment system called CurrentC. One of MCX’s primary members is Wal-Mart, which has said that it has no plans to support Apple Pay at its stores.

“There are certainly a lot of compelling technologies being developed, which is great for the mobile-commerce industry as a whole,” said a Wal-Mart spokesperson to Business Insider. “Ultimately, what matters is that consumers have a payment option that is widely accepted, secure, and developed with their best interests in mind. MCX member merchants already collectively serve a majority of Americans every day. MCX’s members believe merchants are in the best position to provide a mobile solution because of their deep insights into their customers’ shopping and buying experiences.”

The appeal of CurrentC is obvious for retailers. It pulls funds directly from the customer’s bank account and bypasses credit card transaction fees, which is around 2 percent or 3 percent of the total transaction, and helps increase profits for retailers. According to the Nilson Report, $66 billion in credit card fees was paid by retailers in 2013 out of the $4.5 trillion that was spent.

Recently, CVS and Rite Aid took steps to prevent Apple Pay from being used in their stores, a move that Apple CEO Tim Cook referred to as a “skirmish” in the battle between Apple Pay and CurrentC. Both stores are members of MCX and are promoting CurrentC which is expected to launch next year.

But with Wal-Mart preventing the use of Apple Pay, the situation can no longer be a “skirmish.” Especially when MCX can boast that other large retail businesses, such as Best Buy and Target, are members of the organization. However, MCX said that it doesn’t prohibit its members from using CurrentC exclusively and that companies “make their own decisions about what solutions they want to bring to their customers.” Target, though a member of MCX, will accept CurrentC and Apple Pay payments.

Even then, the question of which merchant businesses will not support Apple Pay is a valid one. Many large retailers, and an assortment of US gas station chains, will support CurrentC while Apple only has 34 Apple Pay partners and the banks in its corner.

How many other businesses do you think will prevent consumers from using Apple Pay?